1. Field of the Invention
The present invention relates to a discharging device configured to discharge a sheet with correcting curls of the sheet at its lateral edges resulting from heat generated during a toner fixing process and to an image forming apparatus including the discharging device.
2. Description of the Related Art
An image forming apparatus generally fixes a toner image to a sheet passing between a heating roller and a pressure roller after the sheet is subjected to an image forming process to form the toner image. The sheet may be curled due to heat transferred thereto during the fixing process.
As a method for correcting curls of a sheet, an image forming apparatus may include curtain members for correcting the curls of the sheet. The curtain members are, for example, configured to press lateral edges of the sheet curled upward immediately while the sheet is discharged onto a discharge tray. While the sheet is discharged onto the discharge tray, the curled lateral edges of the sheet are pressed by the curtain members, so that the surface of the sheet is restored to a straight surface. The curtain members may temporarily or instantaneously correct the curls, but it does not completely correct the curls of the sheet. Therefore the sheet on the discharge tray is curled again.
As another method for correcting curls of the sheet, the image forming apparatus may include pressing plates pivotably hanging down. The pressing plates are, for example, configured or arranged to press the lateral edges of the sheet on the discharge tray. The lateral edges of the sheet on the discharge tray are pressed by the pressing plate, so that a preceding sheet may not interfere with a subsequent discharge of the sheet.
These methods, however, may be applied only to a single size of the sheet. For example, the curtain members or the pressing plates deployed to press the lateral edges of the largest sheet may not press those of smaller sheet. Therefore, curls of the smaller sheets may not be corrected.